1. Field of the Invention
This invention relates to vertical milling machines, including an improved tool holding arrangement to permit those vertical milling machines to be utilized more efficiently.
2. Prior Art
Metal milling machines have been around for many years. One very common milling machine is the Bridgeport type, universal, standard vertical milling machine. The Bridgeport milling machine may be characterized by a vertical spindle, which is manually activated by a pull handle, to move a tool towards and push it away from the surface of an article to be worked. A collet is utilized to hold a specific tool in the lower end of the tool spindle of the Bridgeport type machine. A tool is inserted in the collet and the "Z" axis is set, and the tool is ready to work on a workpiece. When a new tool is needed, the collet is removed from the spindle, and the tool is removed from the collet, and the new tool inserted in its place. The collet is reinserted in the spindle, the "Z" axis is re-measured, and the new tool is applied to the workpiece. The original tool may need to be re-used, so that the process is again repeated by reinserting the tool in the collet and the "Z" axis again re-measured. The collet is needed because it provides a machined surface so as to accurately mate with the spindle, thereby maintaining accuracy of the tool during it's milling operation. This type of collet may be known under its common name as an "R-8" collet.
It is an object of the present invention to provide an efficient arrangement for operating a milling machine by saving time typically consumed in the production run of that machine.
It is a further object of the present invention to provide a collet for a Bridgeport type universal milling machine, wherein a succession of different tools may be utilized more than once by that particular Bridgeport type universal milling machine without successive "Z" axis (longitudinal) correction after the initial tool in it's initial collet has been properly set therein.
It is a further object of the present invention to provide a method and apparatus, for holding and re-using a tool in a vertical milling machine in a simple and readily adaptable format, to minimize production time typically required of the machine.